The present invention relates to the production of carbon black and, more particularly, to a method and apparatus for producing an extended structure SRF grade carbon black.
As is known in the art, semi-reinforcing furnace carbon blacks (SRF) are those which meet or fall within the specification set out in ASTM designation N761. In this regard, a number of prior art methods have been proposed and developed for producing a standard SRF grade of carbon black having a DBP oil absorption value of approximately 100. A higher structure of SRF carbon black, with DBP values in the range of 105-110 has also been produced by using feedstock additives and carefully controlling the air, fuel gas, and feedstock flow rates. Some relatively high structure carbon black has also been produced in furnaces with combustion chambers of a particular configuration. None of these prior art techniques have, however, been successful for producing an SRF carbon black with an extended structure, i.e., DBP oil absorption value as high as 130, without sacrificing the rubber reinforcing qualities of the carbon black.